toy with some ideas

README.md

@@ -1,11 +1,20 @@
 ## md2gmi
 
-Convert Markdown to Gemini Gemini [gemtext](https://gemini.circumlunar.space/docs/gemtext.gmi)
-markup with Go. Working with streams and pipes for UNIX like behavior utilizing Go channels.
+Convert Markdown to Gemini [gemtext](https://gemini.circumlunar.space/docs/gemtext.gmi) markup with
+Go. Working with streams and pipes for UNIX like behavior utilizing Go channels. Processing streams
+line by line is deliberately slightly more challenging than it needs to be to play around with go
+state machines.
+
+<!-- testing markdown, this should be deleted, below merged -->
+See the [gemini
+protocol](https://gemini.circumlunar.space/).
+
+Internally md2gmi does a 1st pass that constructs the core layout for gemtext. This is then streamed
+to the 2nd pass line by line. The 2nd pass will convert links and stream line by line to the output.
 
 ### Usage
 
-```
+```plain
 Usage of ./md2gmi:
   -in string
         specify a .md (Markdown) file to read from, otherwise stdin (default)

main.go

@@ -45,13 +45,40 @@ func writer(out string) (io.Writer, error) {
 	return os.Stdout, nil
 }
 
-func write(out string, data <-chan []byte, quit chan struct{}) error {
+func write(w io.Writer, b []byte) {
+	fmt.Fprintf(w, string(b))
+}
+
+type ow struct {
+	w    io.Writer
+	quit chan struct{}
+}
+
+func NewOw(w io.Writer, quit chan struct{}) *ow {
+	return &ow{w: w, quit: quit}
+}
+
+func (m *ow) Input(data <-chan []byte) {
+	for {
+		select {
+		case <-m.quit:
+			return
+		case b := <-data:
+			write(m.w, b)
+		}
+	}
+}
+
+func writesetup(out string, data <-chan []byte, quit chan struct{}) error {
 	w, err := writer(out)
 	if err != nil {
 		return fmt.Errorf("writer: %w", err)
 	}
 
-	NewParser(data, w, quit).Parse()
+	sink := NewOw(w, quit)
+	sink.Input(data)
+
+	//NewParser(data, w, quit).Parse()
 
 	return nil
 }
@@ -73,7 +100,7 @@ func main() {
 		close(quit)
 	}()
 
-	if err := write(out, data, quit); err != nil {
+	if err := writesetup(out, data, quit); err != nil {
 		fmt.Fprintf(os.Stderr, err.Error())
 	}
 }

parser.go

@@ -16,6 +16,9 @@ type fsm struct {
 	quit   chan struct{}
 	data   <-chan []byte
 
+	// if we have a nested state, e.g. a link inside a paragraph
+	returnState stateFn
+	// if we have a termination rule to abide, e.g. implied code fences
 	pending []byte
 }
 
@@ -128,3 +131,8 @@ func paragraph(m *fsm, data []byte) stateFn {
 	m.buffer = append(m.buffer, data...)
 	return paragraph
 }
+
+func link(m *fsm, data []byte) stateFn {
+
+	return link
+}

pipeline.go

@@ -0,0 +1,13 @@
+package main
+
+type Node interface {
+	Pipeline(<-chan []byte) <-chan []byte
+}
+
+type Source interface {
+	Input() <-chan []byte
+}
+
+type Sink interface {
+	Output(<-chan []byte)
+}